1. Field of the Invention
The present invention relates generally to motorcycles and more particularly to two-wheeled motorcycles of the type including a radiator or a like heat-dissipating device for cooling the power propelling unit.
2. Description of the Prior Art
With conventional two-wheeled motorcycles of the type concerned in which the power unit, arranged between the front and rear wheels, is covered by a cowling structure and the heat-dissipating device is arranged at the front of the power unit, any increase in air passage area of the heat-dissipating device, intended to improve the cooling capacity of the latter, must result in a substantial increase in air resistance of the vehicle, making it difficult to employ any large-sized heat-dissipating device.
On the other hand, any substantial reduction in sheet thickness of the cowling structure, intended for reduction in weight of the vehicle, must result in reduction in rigidity of the cowling structure, rendering the latter liable to vibrate as under wind pressure during vehicle travel. This makes it necessary to provide the cowling structure with some reinforcing members; however, use of such members should be avoided as far as possible to minimize the resulting increase in vehicle weight.